The critical need for a better surgical instrument and a better technique for detaching the posterior portion of the menisci (both medial and lateral) has long been recognized. No difficulty is encountered in removal of the anterior portion (i.e. in front of the collateral ligament) since it is readily visible and is easily accessible for sharp dissection detachment. The posterior portion of the menisci (i.e. behind the collateral ligament) is an entirely different matter. It is not visible and is almost inaccessible; hence, a precise controlled detachment at the periphery of the meniscal base is impossible with prior art methods and instruments. Present instruments (i.e. Lowe-Breck and Smillie knives) are essentially a handle with a curved shaft having a concave sharpened end which is pushed manually more or less blindly around the periphery of the meniscus in an attempt to detach the meniscus. Most often the synovial attachment to the meniscus is mutilated as is the meniscus. These instruments are mechanically ineffective and damaging to the posterior knee joint. Even when a second incision is made behind the collateral ligament in an attempt to obtain clearer view of the posterior part of the meniscus, the small incision, compactness of the anatomic structures and the depth of the meniscus again make the use of the Lowe-Breck and Smillie knives imprecise, mechanically difficult, and damaging. The mechanical performance of these knives leave very much to be desired.
There are, of course, surgical instruments which utilize a flexible blade sliding in two parallel grooves. For example, U.S. Pat. No. 2,131,780 to Story entitled, "Adenotome", issued Oct. 4, 1938, refers to an adenotome of the rigid type, as follows: The "moving part of the frame is secured to a blade which moves in a curved track formed by parallel-wall grooves, opening toward each other and the forward end of this blade is sharpened to provide the cutting element." While the quoted passage applies literally to an element of my new meniscatome, there is no teaching in that, or in other adenotome patents, of an instrument suitable for a meniscectomy, for at least two reasons. First, the two blade guides of the adenotome are in a permanently fixed relation. Those of my meniscatome come apart, to allow the grooved blade guides to be placed within a knee joint. No adenotome could ever be placed in the posterior knee joint for meniscectomy. The second reason is that the shape of the adenotome guides is contoured and shaped to fit into the posterior pharynx but could never be introduced into the posterior knee in relation to the periphery of the meniscus as is necessary for meniscectomy.
Other patents showing grooved guides for a flexible cutting blade include Grieshaber U.S. Pat. No. 2,258,287, issued Oct. 7, 1941, for an "adenotome"; Diamant U.S. Pat. No. 1,339,692, issued May 11, 1920, for an adenotome; and Storz 2,843,128 issued July 15, 1958, for an "Adenotome".
The primary object of this invention is to provide an instrument that will assist a surgeon in performing a meniscectomy.
Another object of this invention is to provide an instrument useful in performing a meniscectomy in which the operation can be performed with precision and exactness in an improved manner.
A further object of the invention is to provide an instrument for performing a meniscectomy in which there is a cleaner and smoother cut of the meniscus in an intra-articular fashion at the meniscal base than has previously been possible as regards the posterior meniscus.
Still another object of the invention is to provide an instrument for performing a meniscectomy with less bleeding from the posterior synovia than is often produced by conventional surgical instruments and by special meniscal instruments, such as the Lowe-Breck or Smillie knives.
An additional object of the invention is to provide a surgical instrument that will reduce the time and trauma required for performing a meniscectomy.
Moreover, it is the object of the invention to provide an instrument that will reduce the recovery time for a patient who has had a meniscectomy.
Still another object of the invention is to provide an instrument which will eliminate the need for a second incision into the joint posteriorly for detachment of the posterior meniscus.